How to ID a Small Block Engine Block:

Many people ask how do I find out what a small block engine is? You can find out alot about it if you know where to look....

The first question is: "How do I know what size it is?" That can be easily found out by looking at the driver's side of the block (the one without the oil filter). The casting number is found on the driver's side (left side) of the block as shown here:

Here is a close up of the casting number. You can see that the engine size is cast into the block at the end of the casting number. This is one for a 360:

Now you want to go to the passenger side (right side) of the block where the oil filter mounting pad is for more juicy info. Here is what you are looking for in the picture.

A. This is the VIN pad. This is where the last 8 digits for the vehicle's VIN number that is usually found on the dash board. You can decipher what model year vehicle the engine came in, and the assembly plant that the vehicle was made in. The last 6 digits are the sequence number from the VIN found on the dash board. This number needs to match the last 8 digits of your VIN plate on the dash to be a "Numbers Matching" engine for your car:

B. This is the casting date for the block with the clock to show what time it was cast.

C. This is the shift that the block was cast on at the casting factory, D is for day shift, N is for night shift:

Here is a close up of the casting date and shift on the side of the block:

Here is a close up of the VIN pad. This is where the last 8 digits for the VIN number for the vehicle that it came from the factory. The first digit is the model year that the vehicle that the engine originally came in. The second digit will tell you what vehicle assembly plant built the vehicle. The last 6 digits are the sequence number for the VIN. These can be hard to see as they get covered with paint, grease, and grime, so you may need to do some scraping to find it and read it:

Here's a chart to decode the whole vehicle VIN number:

On the front of the block under the driver's side (left side) head, you will find another batch of numbers stamped into the block. This is the information from the engine assembly plant. Like the VIN pad above, it can be covered in paint, grease, and grime; so you may have to do some scraping and cleaning to see it.

Here's a close up of where you will find the information:

Here's the chart to decode the engine plant information:

Good luck and have fun!

Here's some additional info that Rocky_JS added to help us:

Some additional stuff I have saved. These are the special engine assembly codes.

With some of the over/undersized components you may see a 4 or 4I or 4E. These will equate to cyl number 4 and/or 4 Intake or Exhaust. Sometimes not noted at all as to which cyl has oversized lifter etc.